.303 British
.303 British, or 7.7x56mmR, is a .303-inch (7.7mm) caliber rifle and machine gun cartridge first developed in Britian as a blackpowder round put into service in December 1888 for the Lee-Metford rifle, later adapted to use smokeless powders. It was the standard British and Commonwealth military cartridge from 1889 until the 1950s when it was replaced by the 7.62x51mm NATO. __FORCETOC__ Cartridge Specification Case measurements The measurement .303 inch is the nominal size of the bore measured between the lands which follow the older blackpowder nomeclature. Measured between the grooves, the nominal size of the bore is .311 inch. Bores for many .303 military surplus rifles are often found ranging from around .309-in up to .318-in. Recommended bullet diameter for standard .303 cartridges is .312-in. Gunpowder The original .303 service cartridge employed black powder as a propellant, and was adopted for the Lee-Metford rifle, which had a rifleing designed to lessen fouling from this propellant. The Lee-Metford was used as a trial platform by the British Committee on Explosives to experiment with many different smokeless powders then coming to market, including Ballistite, Cordite, and Riflelite. Ballistite was a stick-type smokeless powder composed of soluable nitrocellulose and nitroglycerine. Cordite was a stick-type or 'chopped' smokeless gunpowder composed of nitroglycerine, gun-cotton, and mineral jelly, while Riflelite was a true nitrocellulose powder, composed of solualbe and insoluable nitrocellulose, phenyl amidazobense, and volatiles similar to French smokeless powders. Unlike Cordite, Riflelite was a flake powder, and contained no nitroglycerine. Excessive wear of the shallow Lee-Metford rifling with all smokeless powders then available caused ordnance authorities to institiue a new type of barrel rifling designed to increase barrel life; the rifle was then referred to thereafter as the Lee-Enfield. After excessive testing, the Committee on Explosives selected Cordite for use in the Mark II .303 British service cartridge. Bullet The initial .303 Mark I and Mk II service cartridges employed a 215-grain, round-nosed, cupro-nickel full metal jacketed bullet with a lead core. After tests determined that the service bullet had too thin a jacket when used with cordite, the Mk II bullet was introduced, with a flat base and thicker cupro-nickel jacket. History and development During a service life of over 70 years with the British Commonwealth armed forces, the .303-inch cartridge in its ball pattern progressed through ten marks which eventuallty extended to a total of about 26 variations. The .303 cartridge has seen much sporting use with surplus military rifles, especially in Australia, Canada, New Zealand, and to a lesser extent, in the US and South Africa. In Canada, it was found to be adequate for any game except the great bears. In Australia, it was common for military rifles to be re-barreled in .303/25 and .303/22. In South Africa .303 British Lee-Enfield rifles captured by the Boers during the Boer War were adapted for sported purposes and became popular with many hunters of non-dangerous game, being regarded as adequate for anything from the relatively small impala, to the massive eland and kudu. The Mk II round-nosed bullet was found to be unsatisfactory when used in combat, particularly when compared the the dum-dum rounds issued in limited numbers in 1897 during the Chitral and Tirah expeditions of 1897/98 on the Northwest Frontier of India. This led to the introduction of the Cartridge S.A. Ball .303 inch Cordite Mark III, basically the original 215-grain bullet with the jacketing cut back to expose the lead in the nose. Similar hollow-point bullets were used in the Mk IV and Mk V loadings, which were put into mass production. The design of the Mk IV hollow-point bullet shifted weight rearwards, improving stability and accuracy over the regular round-nose bullet. These soft-nosed and hollow-point bullets, while effective against human targets, had a tendency to shed the outer jacket upon firing; the latter occasionally stuck in the bore, causing a dangerous obstruction. To replace the Mk II,IV, and V, the Mark VI round was introduced in 1904, using a round nose bullet similar to the Mk II, but with a thinner jacket designed to produce some expansion, though this proved not to be the case. Japanese 7.7mm ammunition Japan produced a number of machine guns that were direct copies of the British Lewis and Vickers machine guns including the ammunition. These were primarily used in Navy aircraft. The 7.7mm cartridge used by the Japanese versions of the British guns is a direct copy of the .303 rimmed cartridge and is distinctly different from the 7.7x58mm Arisaka rimless used in other Japanese machine guns and rifles. Note: Standard Japanese ball ammunition was very similar to the British Mk 7 cartridge. The two had identical bullet weights and a "tail-heavy" design, as can be seen in the cut-away diagram. Military surplus ammunition Military surplus .303 British ammunition is often availiable, notably at gun shows and from online dealers. It may or may not have corrosive primers. Care must be taken to identify the round properly before purchase or loading into weapons. Cartridges with the Roman numeral VIII on the headstamp are the Mark 8 round, specifically designed for use in the Vickers machine guns. Although Mark 8 ammunition works well in a Vickers gun, it should not be used in rifles because the boat-tailed design causes increased barrel wear. The boat-tailed bullet design of Mk 8 ammunition is not in itself a problem. However, when combined with the Cordite propellant used in Mk 8 cartridges, which burns at a much highter temperature than nitrocellulose, there is increased barrel erosion. The cumulative effects of firing Mk 8 ammunition through rifles were known of during the Second World War, and British riflemen were ordered to avoid using it, except in emergencies. The best general-purpose ammunition for any .303 rifle is the Mark 7 design because it provides the best combination of accuracy and stopping power. There is no problem with using ammunition loaded with corrosive powders, providing that the gun is thoroughly cleaned after use to remove the corrosive salts. Category:Western Nations Category:Weapons